Eliminating the second-order ionospheric error in dual-frequency global navigation satellite systems

摘要

Errors in Global Navigation Satellite Systems (GNSS) measurements, which occur during receiver positioning, are largely associated with the presence of an inhomogeneous dispersive medium (ionosphere) between a satellite and a receiver. In common dual-frequency measurements, only the first-order ionospheric error can be eliminated. The necessity of taking into account the higher-order ionospheric errors stems from high accuracy requirements to receiver positioning (of order of millimetres) for some applications. It has been found before that the second-order error, associated with the geomagnetic field, is approximately proportional to the first-order error. This fact not only simplified the calculation of the second-order error, but provided a method of dual-frequency measurements that can simultaneously eliminate the first- and second-order errors. Here we verify this method by numerical simulation and show possibility of dual-frequency GNSS measurements with the accuracy of order of millimetres.